[LON-CAPA-users] correct answer changing to incorrect

James Mueller lon-capa-users@mail.lon-capa.org
Wed, 08 Dec 2010 18:23:26 -0500


Stuart,
	Ok skip last question, just needed to show all details.  All submissions were from the math departments access server.  

Transaction 1 pittmath1 130.49.17.207 INTERNAL NO_UNIT  0.0490 NO_UNIT    incorrect_attempted                     Sun Nov 21 06:34:31 pm 2010 (EST)  
Transaction 2 pittmath1 130.49.17.207 INTERNAL INCORRECT  0.0490 m INCORRECT   0 incorrect_attempted 1                    Sun Nov 21 06:34:33 pm 2010 (EST)  
Transaction 3 pittmath1 130.49.17.207 INTERNAL APPROX_ANS  2.0944 m APPROX_ANS 1   correct_by_student 2                    Sun Nov 21 06:35:54 pm 2010 
... 
Transaction 9 pittmath1 130.49.17.207 INTERNAL INCORRECT  0.0490 m INCORRECT    incorrect_attempted 1                    Tue Nov 30 05:10:17 am 2010 (EST) 

If he had multiple windows open on his computer, is it possible that the first 3 submissions were from one window, which he then closed.  Then he comes back from Thanksgiving break and notices the other window, forgets that he already did it and submits an incorrect answer, making the same mistake he did the first time he did the problem.

If one somehow view a problem in multiple windows (or tabs), if you submit something in one window, what needs to happen for that to be reflected in the second window?

-Jim

On Dec 8, 2010, at 4:51 PM, Stuart Raeburn wrote:

> Hi,
> 
> The timestamp of Tue Nov 30 05:10:17 am is significant here.
> 
> 5.10 am is the time LON-CAPA servers check their connections with  
> other servers in the network, and resend any critical transactions to  
> library servers which could not be completed when submission  
> originally occurred.
> 
> One possibility is that the student was logged in to a server other  
> than the library server, when the student's submission on part 11 was  
> made, and the server was unable to complete the transaction to store  
> it on the pitt.edu library server.  Given that part 11 was graded  
> correct on 11/21, if this submission occurred after that date, but  
> before the due date on 11/29, then correctness and tries information  
> must also have not been transferred from library server to session  
> server initially; hence a try was allowed and this was "Trial 1" as  
> far as the access server was concerned.
> 
> When pending transactions were re-tried the next morning the store on  
> the library server was successful. I recommend looking at the  
> submission history to see which LON-CAPA host was hosting the  
> student's session for this submission:
> 
> Tue Nov 30 05:10:17 am 2010 (EST)Part: 11 (ID 12) Trial 1  0.0490 m
> Part: 11  incorrect
> 
> Stuart Raeburn
> MSU LON-CAPA group
> 
> Quoting James Mueller <mueller@pitt.edu>:
> 
>> More details on this problem.
>> 
>> If I check grades, he does have credit for getting this one correct.  
>>  It is just that when he looks at the problem, it is displayed as   
>> incorrect answer.  The other thing I don't understand is the due   
>> date for this problem was Nov. 29, so where does this incorrect   
>> submission on Nov 30 come from?
>> 
>> -J. Mueller
>> 
>> On Dec 8, 2010, at 3:51 PM, James Mueller wrote:
>> 
>>> A student just complained that he solved a problem but later Lon   
>>> Capa said he was incorrect.  I looked at his submissions and see   
>>> the following.  From the submissions, it looks like he completed   
>>> every part of the problem on Nov 21, but on Nov 30, his first   
>>> incorrect answer for the first part appears to be entered again,   
>>> and it is listed as the first trial.  I can give him credit for   
>>> getting this correct, but does anyone have any ideas as to how this  
>>> might happen?
>>> 
>>> -Jim Mueller
>>> 
>>> Sun Nov 21 06:34:31 pm 2010 (EST)Part: 11 (ID 12) Trial not counted  0.0490
>>> Part: 11  no_unit
>>> Sun Nov 21 06:34:33 pm 2010 (EST)Part: 11 (ID 12) Trial 1  0.0490 m
>>> Part: 11  incorrect
>>> Sun Nov 21 06:35:54 pm 2010 (EST)Part: 11 (ID 12) Trial 2  2.0944 m
>>> Part: 11  approx_ans
>>> Sun Nov 21 06:38:14 pm 2010 (EST)Part: 13 (ID 14) Trial not   
>>> counted  284.8377 m/s
>>> Part: 13  sig_fail
>>> Sun Nov 21 06:38:19 pm 2010 (EST)Part: 13 (ID 14) Trial 1  284.81 m/s
>>> Part: 13  incorrect
>>> Sun Nov 21 06:38:23 pm 2010 (EST)Part: 13 (ID 14) Trial 2  284.84 m/s
>>> Part: 13  incorrect
>>> Sun Nov 21 06:39:19 pm 2010 (EST)Part: 13 (ID 14) Trial 3  45.33 m/s
>>> Part: 13  approx_ans
>>> Sun Nov 21 06:41:29 pm 2010 (EST)Part: 15 (ID 16) Trial 1  6.66 m/s
>>> Part: 15  approx_ans
>>> Tue Nov 30 05:10:17 am 2010 (EST)Part: 11 (ID 12) Trial 1  0.0490 m
>>> Part: 11  incorrect
> 
> 
> 
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